Answer
4
Work Step by Step
Based on the definition of $a^{\frac{m}{n}}$, we know that $a^{\frac{m}{n}}=(\sqrt[n] a)^{m}=\sqrt[n] a^{m}$ (where $\sqrt[n] a$ is a real number).
Therefore, $16^{\frac{1}{2}}=\sqrt[2] 16^{1}=\sqrt 16=4$.
We know that $\sqrt 16=4$, because $4^{2}=16$.